Profit Refer back to Exercise 57, and now suppose that each hardcover book...

Profit Refer back to Exercise 57, and now suppose that each hardcover book costs the stores $10, each softcover book costs $5, and each plastic book costs $10. Use matrix operations to compute the total profit at each store in January. HINT [See Example 5.]

Revenue Recall the Left Coast Bookstore chain from the preceding section. In January, it sold 700 hardcover books,1,300 softcover books, and 2,000 plastic books in San Francisco; it sold 400 hardcover, 300 softcover, and 500 plastic books in Los Angeles. Now, hardcover books sell for $30 each, softcover books sell for $10 each, and plastic books sell for $15 each. Write a column matrix with the price data and show how matrix multiplication (using the sales and price data matrices) may be used to compute the total revenue at the two stores. HINT [See Example 5.]

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